The Fio board allows use of Xbee for wireless sketch downloads.Have you looked at this page?http://arduino.cc/en/Main/ArduinoBoardFioProgramming

Thanks, I had not seen that. It does look very similar to the Adafruit tutorial onsame, and neither of them really describes the comms protocol, but only howto configure the breakout boards. I'd still like to understand how it actually works. :-) But pretty soon, I've probably just have to go ahead and do it, and not worry about the nuts'n'bolts.